This project is concerned with the metabolism of two homopolymers of glucose which are synthesized by filamentous fungi: glycogen and nigeran. We will purify and characterize several key enzymes of the glycogen cycle of Neurospora crassa. These include phosphorylase a, phosphorylase b, phosphorylase b kinase, phosphorylase a phosphatase and a cyclic AMP-independent protein kinase. We will attempt to establish the manner in which the enzymes of the glycogen cycle in Neurospora are regulated. Nigeran ( mycodextran) is a linear polysaccharide composed of alternating alpha-1,4 and alpha-1,3 linked glucose residues. The polysaccharide is accumulated by many Penicillium and Aspergillus species under conditions of low pH and nitrogen deficiency. We hope to establish the enzymes involved in its biosynthesis, and the relationship between the physiological conditions favoring nigeran accumulation and the activity and levels of the enzymes involved. Standard techniques of protein chemistry and enzymology will be employed.